Expansible tube plug



Dec. l2, 1950 A. A. coNKLlN Erm.

EXPANSIBLE TUBE PLUG Filed Nov. 26, 194e Patented Dec. 12, 17950 EXPANSIBLE TUBE PLUG Alfred A. Conklin, West Haven, and Raymond G. Sherman, North Haven, Conn.

Application November 26, 1946, Serial No. 712,290

3 Claims.

This invention relates to an improvement in tube-plugs and particularly to plugs for insertion into ends of condenser tubes which, from some cause, leak.

The object of this invention is to form a plug which may be readily inserted into the end of a condenser tube and adjusted to close the end of such a tube.

With the above and other objects in view, as will appear to those skilled in the art from the present disclosure, this invention includes all features in the said disclosure which are novel over the prior art.

In the accompanying drawings, in which certain modes of carrying out the present invention are shown for illustrative purposes:

Fig. 1 is a side View of a plug embodying my invention;

Fig. 2 is an inner end view of the same;

Fig. 3 is an outer end view;

Fig. 4 is a longitudinal sectional view partly in elevation;

Fig. 5 is a longitudinal sectional View showing the plug inserted into a tube;

Fig. 6 is a sectional view on the line 6-6 of Fig. 5;

Fig. 7 is a sectional view, like Fig. 5,l showing the plug expanded; and

Fig. 8 is a sectional view on the line 8-8 of Fig. '7.

The plug as illustrated in the drawings includes a cylindrical body-member I of molded rubber or other suitable material having at its outer end a head II which provides an annular stop-shoulder I2 to limit the distance the plug may be inserted into a tube.

Axially molded in the interior of the bodymember I0 is a tubular sleeve I3 having its outer periphery inwardly tapered and its axial bore provided at its outer end with internal lefthand threads I4. Also at the outer end thereof, the sleeve I3 is formed with an annular anchoring-flange I embedded in the head-portion of the body-member I Il and having its outer surface knurled or otherwise roughened so as to firmly hold the sleeve I3 against any turning movement with respect to the body-member. The flange I5 also serves to prevent any axial displacement of the sleeve I3 relative to the body-member I0, for the purpose as will hereinafter appear.

A tubular nut I1 formed with a shoulder I6 is also molded in the body-member I Il axially with respect to both the said body-member and sleeve I3.

At the inner end of the nut I1 is formed anv anchoring-head I8, the outer face of which constitutes the shoulder I6 before referred to. The body-portion of the nut I'I is of a diameter to freely t within the smooth unthreaded inner portion of the sleeve I3. Like the ilange I5 of the sleeve I3, the head I8 is knurled or otherwise roughened so as to firmly anchor the nut I1 against any turning movement relative to the body-member. The nut II is provided axially with right-hand threads for threaded engagement with the similarly-threaded shank I9 of a screw 2B.

The screw 20, in addition to the right-hand threaded shank I9, has its body-portion 2| provided with left-hand threads coacting with the left-hand threads I4 of the sleeve I3. At its outwardly-projecting end, the body-portion 2| is provided with a kerf 22 for the reception of a screw driver or other suitable tool.

As shown in Fig. 4, when the elements above described are assembled for molding the bodymember I0, an internally-threaded cap 23 is threaded over the projecting outer end of the body-portion 2| of the screw 20 and serves at this time to protect the exposed threads of the screw 20 from being molded into the body-member. The cap 23 also serves to protect the threads of the screw 20 from harm when the plug is not in use.

When it is desired to use the plug to close off a tube, the screw 20 is threaded into the body-member, causing the sleeve I3 and nut I I to axially move away from each other. This separation of these two elements will cause an extension of the body-member I 0, thereby increasing the over-all length of the body-member, while at the same time decreasing its diameter.

When the diameter of the body-member is small enough to enter a condenser tube such as 24 (Fig. 5), the plug is inserted to a suicient depth or until the shoulder I2 engages the end of the tube. The screw 20 may now be backed-oli, drawing the sleeve I3 and nut I1 axially together, thus permitting the body-member to axially contract and expand its diameter until this expansion is arrested by the engagement of the body-member with the interior Wall of the tube 24 (Fig. 7)

The continued unthreading or backing-oil. of the screw 20 will forcibly further expand the body-member III into rm gripping engagement with the interior of the tube 24 and eiectively close the otherwise open end of the tube.

When it is desired to remove the plug, the screw 20 is threaded into the plug, to again extend and decrease the diameter of the bodymember I0, allowing the removal of the plug.

It will thus be seen that the plug of the present invention readily and effectively may be inserted in a tube to plug or close the end thereof or to be removed therefrom.

The invention may be carriedy out in other specic ways than those herein set forth Without departing from the spirit and essential characteristicsl of the invention, and the present embodiments are, therefore, to be considered inall respects as illustrative and not restrictive, and all changes coming Within the meaning and equivalency range of the appended claims are intended to be embraced therein.

We claim:

l. A tube plug comprising a molded rubber body closed at one end and having an axial aperture intersecting its opposite open end; and means mounted in the' axial aperture of said body for positively expanding and contracting said plug laterally, said means comprising an internally-threaded Sleeve molded in situ in the open end of said body, an internally-threaded nut molded in situ the closed end of said body in axial alignment with said sleeve, the threads' of said. nut being reverse to the threads of said sleeve, and an externally-threaded screw in the open end of said body, said screw having reversely-threaded sections arranged to engage said threaded sleeve and said threaded nut respectively to move said sleeve and nut axially simultaneously and in opposite directions thereby to positively' elongate and positively contract the rubber body of said plug.

2. A tube plug comprising a molded rubber body closed at one end and having an axial aperture intersecting its opposite open end; an integral flanged head on said body at its open end; and screw-threaded means mounted in the axial aperture of said body for positively expanding and contracting the molded rubber body lateral- 1y, said screw-threaded means comprising an internally-threaded sleeve molded in situ in the flanged head of said body, an internally-threaded nut moldedA in situ in the closed end of said body in axial alignment with said sleeve, the threads of said nut being reverse to the threads of said sleeve, and an externally-threaded screw in the open end of said body, said screw having reversely-threaded sections arranged to engage said threaded sleeve and said threaded nut respectively to move said sleeve and nut axially simultaneously and in opposite directions thereby to positively elongate and positively contract the rubber body of said plug.

. 3. A tube plug comprising a molded rubber body closed at one end and having an axial aperture intersecting its opposite open end; an integral flanged head on said body at its open end; and screw-threaded means mounted in the axial aperture of said body for positively expanding and contracting the molded rubber body laterally, saidV screw-threaded means comprising an internally-threaded sleeveY having a ange at one end molded in situ in the flanged head of. said rubber body, an internally-threaded nut having a flange at one end molded in situ in the closed end of said body, .saidV nut being in axial alignment with said sleeve and` the threads of said nut being reverse tothe threads of said sleeve; and an externally-threaded screw in the open end of said body, said screw having reversvelythreaded sections arranged to engage said threaded sleeve and said threaded nut respectively to move said sleeve and nut axiallyv simultaneously and in opposite directions thereby tol positively elongate and positively contract the rubber body of said plug.

ALFRED' A. CONKLIN. RAYMOND G. SHERMAN.

REFERENCES CTED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 778,068T Peterson Dec. 20, 1904 922,544 Turner et al.A May 25, 1909l 2,062,519 Liungberg Dec. 1, 1936 2,355,492 White Aug. 8, 1944 2,374,947 4 NchOlSOn May 1, 1945 

